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4dd8e7c0 | 1 | /* Array allocation from a fixed-size buffer. |
688903eb | 2 | Copyright (C) 2017-2018 Free Software Foundation, Inc. |
4dd8e7c0 FW |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
17 | <http://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <alloc_buffer.h> | |
20 | #include <malloc-internal.h> | |
21 | #include <libc-pointer-arith.h> | |
22 | ||
23 | void * | |
24 | __libc_alloc_buffer_alloc_array (struct alloc_buffer *buf, size_t element_size, | |
25 | size_t align, size_t count) | |
26 | { | |
27 | size_t current = buf->__alloc_buffer_current; | |
28 | /* The caller asserts that align is a power of two. */ | |
29 | size_t aligned = ALIGN_UP (current, align); | |
30 | size_t size; | |
31 | bool overflow = check_mul_overflow_size_t (element_size, count, &size); | |
32 | size_t new_current = aligned + size; | |
33 | if (!overflow /* Multiplication did not overflow. */ | |
34 | && aligned >= current /* No overflow in align step. */ | |
35 | && new_current >= size /* No overflow in size computation. */ | |
36 | && new_current <= buf->__alloc_buffer_end) /* Room in buffer. */ | |
37 | { | |
38 | buf->__alloc_buffer_current = new_current; | |
39 | return (void *) aligned; | |
40 | } | |
41 | else | |
42 | { | |
43 | alloc_buffer_mark_failed (buf); | |
44 | return NULL; | |
45 | } | |
46 | } | |
47 | libc_hidden_def (__libc_alloc_buffer_alloc_array) |